If you tell God no because He won't explain the reason He wants you to do something you are actually hindering His blessing. But when you say yes to Him all of heaven opens to pour out His goodness and reward your obedience. What matters more than material blessings are the things He is teaching us in our spirit.
The promise of America has always been that if you worked hard had the right values took some risks that there was an opportunity to build a better life for your family and for your next generation.